Instantaneous phosphor thermometry applicable to walls exposed to flames

It is important to be able to measure the temperature distribution of walls that are exposed to high temperatures, such as fire walls and internal combustion engines, in order to improve their performance. However, only a few studies have quantitatively visualized the two-dimensional temperature distribution of walls exposed to flames. Phosphor thermometry is a key approach to measuring the temperature distributions of walls, since phosphorescence lifetimes and spectra vary over a wide temperature range.In this study, the luminescence properties of the phosphor, Y2O2S:EuSm, were investigated. Although the temperature sensitivity of its spectral shape was only 0.008%/°C in the range 50–210 °C, that of its luminescence lifetime was 0.78%/°C. Lifetime-based phosphor thermometry was performed using a simple experimental setup consisting of a non-intensified high-speed CMOS camera, a pulsed UV laser, and a phosphor coated with a thin metal film. It was found that the excitation power had little effect on the phosphor lifetime and that the metal film did not affect the phosphorescence lifetime. The temperature measurement uncertainty was determined to be ±4.4 °C from measurements of uniform temperature fields. Instantaneous wall temperature measurements were demonstrated during flame combustion in a rapid compression expansion machine. The measured temperatures agreed with those measured by a thin thermocouple. The proposed system is capable of measuring the instantaneous wall temperature even in a combustion chamber.

► We propose a visualization method of temperature exposed to combustion flames.
► The temperature map was obtained in a few hundreds microseconds.
► A lifetime-based approach was adopted.
► This study investigates the luminescence properties of the phosphor, Y2O2S:EuSm.